This invention relates to steerable skate apparatus, in particular, a wheel suspension for skate apparatus specifically, in-line skates, skateboards and scooters and other personal wheeled transportation devices.
Conventional four wheel roller skates, with a wheel at xe2x80x9ceach cornerxe2x80x9d, are able to steer by leaning the foot to either side. The axles are usually mounted on pivots, which are inclined to the horizontal and incorporate a compliant elastomer block to self-center the steering. Balancing while wearing the skates is fairly natural. Leaning to the right produces a turn to the right and vice versa, which tends to correct the skater""s balance.
With the advent of in-line skates, skate devices including scooters and skate boards in which the wheels are substantially linearly aligned have been developed. In such devices the wheels are rotatablely affixed to the device and an axle or spindle about which the wheel rotates is positionally fixed relative to a frame of the skate device. Steering is accomplished by rotating the linearly aligned wheels at an angle about a vertical axis. That is, the skater points his foot, and therefore the linear alignment of the wheels, in a desired direction. This is an unnatural way of balancing, and it inevitably involves the generation of friction and conflicting forces, sometimes unpredictably so, between the wheels and the road.
In-line skates are popular because the skater can accelerate faster, and they tend to use larger diameter wheels, which reduces rolling resistance.
The present design is that of a steerable in-line skate, which combines the advantages of conventional skates with those of in-line skates. The in-line skate or any such similar apparatus such as a scooter or skateboard, can be steered into a new vector or direction by merely leaning the foot at some desired angle from the vertical, as with a conventional xe2x80x9cquadxe2x80x9d skate, versus having to both lean and rotate the foot about a vertical axis.
According to the present invention, there are provided two or more wheels situated on the longitudinal centerline of the skate. A wheel is situated on or near the skate""s longitudinal centerline at the front of the skate. This wheel steers about an instantaneous axis, which is inclined forward relative to vertical. That is, the horizontal distance between the wheel vertical centerline and the steering axis at the top of the wheel is greater than that at the bottom of the wheel. The steering axis intersects the ground (assumed flat) ahead of the point at which the wheel touches the ground. Thus a caster is produced with an inclined axis.
The steering axis is produced using two pivoted links. The exact position of the steering axis may move slightly as the wheel is turned to the left or the right. Each link comprises two parallel pivots, one at each end. The two links are positioned approximately symmetrically either side of the skate longitudinal centerline. The links are orientated so that the pivots are parallel to the steering axis. The two leading pivots are closer together than the trailing pivots. The trailing pivots are connected via a bracket to the wheel axle or spindle. The leading pivots are connected to the skate frame.
The wheel is asymmetrical and dished in shape to allow the above assembly to be positioned near the skate centerline.
A further wheel(s) is/are positioned to the rear of the skate, also approximately on its longitudinal centerline.
It is possible to use large or small wheels with this design depending on the intended use. Skates with small wheels can be made more compact for greater maneuverability. Large wheel skates are better for use on rough surfaces, or where higher speed is required.